<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    .box{
        width:300px;
        height:300px;
       
        margin:0  auto;
    }
</style>
</head>
<body>
    <div  class="box">
        <img src=" C:\Users\Administrator\Desktop\Javascript\pic_bulboff.gif       "     id="deng"  />
        <input  type="button"      value="开灯"    onclick="keidong(  )"   id="m"   />



    </div>
    <script>
    var  i=1;
    function      keidong(){
      
        
        if(i==1){
        deng.src="pic_bulbon.gif" ;
        m.value="关灯";
      
          i=0;
        
    }else{
     
       
        deng.src="pic_bulboff.gif   " ;
        m.value="开灯";
        
        i=1;

    }
    }


    
    
    
    
    </script>
    
</body>
</html>